Carbon dioxide ice apparatus and process



Nov. 15, 1932. J. V'V..MARTIN, JR ,8

CARBON DIOXIDE ICE APPARATUS AND PROCESS Original Filed Dec. 6, 1926 BY {ATTORNEY Patented Nov. 15, 1932 UNITED STATES PATENT OFFICE JAMES W. MARTIN, JR., 0F YONKERS, NEW YORK, ASSIGNOR TO DRYIGE CORPORATION 01 AMERICA, 01 NEW YORK, N. Y., A CORPORATION OF DELAWARE CARBON DIOXIDE ICE APPARATUS PROCESS Original application filed December-6, 1926, Serial No. 152,754. Divided and this application filed December 15, 1928. Serial No. 326,274.

My present invention includes certainfeatures-set forthin my pending application Ser. No. 152,754, filed December 6, 1926, of which this is a division. It isrelated to the invention set forth in a companion application, Ser. No. 153,064, now Patent No. 1,659,435, granted February 14, 1928,in that it concerns large quantity production of solidified carbon dioxide in the form of socalled carbon dioxide snow and compresslon thereof to form dense, structurally coherent blocks such as are now going into extensive use for refrigeration and similar purposes.

As is well known, carbon dioxide cannot exist as a liquid at atmospheric pressures, but the snow, when formed, is stable at atmospheric pressures and temperatures and can be handled as a commercial product although its evaporation temperature is approximately110 below zero Fahrenheit. Upon melt ing, it simultaneously absorbs the latent heats botli of liquefaction and boiling, thereby sublimating from solid directly to gas form, at atmospheric pressures.

The carbon dioxide snow is produced" from carbon dioxide which is maintained in liquid form by subjecting it to critical temperature and pressure of liquefaction. The liquid is transformed to crystalline or snow formby releasing the pressure to permit sudden gasification of the liquid and expansion of the resultant gas.

My present invention'relates more'particularly to means for compressing the snow into blocks, preferably in an extension of the extremely cold snow forming chamber whereby loss of the carbon dioxide gas is minimized, and the snow is preserved in the cold atmosphere,;insulated from heat until after it has been compressed into blocks, in which form it is in relatively stable condition for extrusion into the open air for use as a finished commercial product.

I have discovered that the production of blocks of dense. tough, structurally sound solid carbon dioxide cannot be accomplished merely by one direction pressure applied by a piston which constitutes one wall of a mold ing chamber. .This is because of the gases that are intimately bound in the pores of the lumps of snow. These lumps consist of broken fragments of the deposit formed in the snow chamber and these deposits consist of crystals that are welded together so as to enclose great quantities of finely subdivided CO gas. In practice, it is found that the moldin pressure expels very little of this gas. onsequently, the gas is highly compressed with and sealed in the snow and this results in a complete block that is under great internal tension, making it structurally weak. Preferably, such expulsion is accomplished by a tamping operation carried outbytamps or crushers that are of much less area than the snow surface against which they strike. The action of the tamps on local areas of the snow mass expels the air and gases through the surface of the snow adjacent the tamps.

This tamping also snugly compacts the mass by breaking down the snow crystals and prepares it for the final compressing and molding operation which forms it into tough,

hard blocks free of gas and air bubbles.

Preferably, the fragmentary masses of snow from the forming chamber fall into a bin of uniform cross-sectional area whereby tapered passageway. The snow, sustained against lateral expansion is tamped down by one or more relatively small, vertically reciprocated, gas-expellingtamps'. v

Subsequently, a cut-off blade or valve may be moved into position to segregate the tamped snow in the bottom of the bin from.

.Fig. 1 is a'longitudinal vertical section- I avoid the. danger of wedging the snow in a 2 2, Fig. 1.

structurally considered, the snow making chamber fully described in the parent application above referred to, includes the inner metal casing 4, of conventional construction, supported in any desired way in an outer metal shell, 5, so as to leave an interspace 6, 6, 6, for circulation of the waste carbon dioxide gas which has an outlet through screen 7 near the discharge end of the chamber. This cold gas is directed primarily downward into the interspace 6a surrounding the collecting bin and compressor described hereafter, from whence it escapes oris' exhausted in any suitable manner, not shown. n

The expansion nozzle, as also the precooling super-compression and follow-up pressure on the supply of the liquid to the nozzle, breaking up'of the snow deposited on the walls of the chamber, etc, may be as set forth ,and claimed in said companion applications. The snow fragments and powder from the snow forming chamber fall into the space 20, which is a hopper for a compressor, comprisinga tubular member, 21, which, as shown'in Fig. 2, is rectangular in cross-section, ex-

- tends transversely of the apparatus, is open at one end. 24, for exit of the compressed 1 product and is closed at the other end by head 22, reciprocated by a power cylinder, screw or other suitable motor means. Its normal retracted position as shown full lines, Fig.

, 2, is just clearing the downward discharge 0 opening of hopper 20. Above the piston is a valve-like plate, 23, sliding in grooves 25,

its forward edge being preferably beveled. as

shown so as to cut through snow when the- -space21 is over-filled. It remains in the closed position, cutting off escape of the snow and serves as a top wall for the compression space when the piston 22 advances to the dotted line position shown in Fig. 2.

For, compressing the first block, a plug or 0 other abutment must lic nsed to sustain the pressure of the plunger agai t the snow, but

thereafter the first block, w, may be pushed to the position in so that each formed blockaffords a compression abutment for each suc- ,ceeding block compressed by the plunger. I

prefer to provide inwardly projecting fingers such as 27 at intervals about the cavity, at a point registering with the rear surface of the second block. When in the projected posieo tion as shown in Fig. 2, they serve to sustain part ofthe thrust pressure of the piston,

. and they may be utilized to assist in maintaining separation of blbcks w and w. a

The fingers 27 ar withdrawn after the block a? has been compressed, to permit the mold box 21; These are reciprocated either by hand or preferably by machinery diagrammatically-indicated at 32, to break up the lumps, release the gas therefrom and tamp down the loose snow and fragments into a fairly uniform mass in the space in front of the plunger, before the plunger advances.

. When the snow is thus tamped, fewer reciprocations'bf the plunger are necessary to form a block of desired size and density and the block will be freefrom compressed gas to -an extent unattainable in any other way.

A'onedirection pressure against the block is in itself inoperative to expel gases since there is no opportunity for the gas to escape. The tamping, however, by tamps of less area than the snow-surface against which they impinge, effectively drives entrapped gas and air out through the top of ,the mass and presents a relatively gas free compact mass of snow to the piston for the final molding operation.

From the above, it will be seen that the apparatus is adapted for efficient snow packing, compressing and ejecting, all in a region near the freezing point of the carbon dioxide, so that there is little waste by melting. During the process and after the block is ejected, it is dense enough to permit a reasonable time for transit through the open'air to a place of storage without appreciable loss. Furthermore, the various steps of the process are continuously progressing and uninterrupted, so that I with apparatus of the capacity above mentioned it will be possible to turn out many tons of commercial carbon dioxideblocks per twenty-four hours.

sure, butmy way of makingsuch blocks has certain advantages under somecommercial conditions often encountered in practice.

I claim:

1. Means for supplying carbon dioxide snow, a mold into which said snow discharges, a reciprocatory plunger in the mold and a cut ofi between saidcarbon dioxide snow supplying means and said mold for closing the mold entrance ening and formin when closed a lateral we 1 of the mold during the compression stroke of the plunger.

2. Means for supplying carbon dioxide snow, a mold into which said snow discharges, a reciprocatory plunger in the mold, means for tamping the snow in the mold while the plunger is retracted, and a cut off for closing the mold entrance opening during the compression stroke ofthe plunger.

3. Means for supplying carbon dioxide snow, an open ended mold into which said snow discharges, saidv mold having one end closed by aretracted reeiprocatory plunger and the other end by a previously compressed block of the snow whereby pressure of the said plunger compresses the intermediate snow and then ejects said previously compressed block, means for tam'ping thesnow in the mold while the plunger is retracted, and

a cut oil for closing the mold entrance during the compression stroke of the plunger. 4. The method of making dense masses of solid carbon dioxide, which includes expanding liquid carbon dioxide to make snow and,

while 'excludingair, partially compacting the snow into a mold and then compressing the tamp' snow in a direction diflerent from that of the compacting.

5. The. method of making dense masses of A solid carbon dioxide, which includes expand-' ing liquid carbon dioxide to make snow and, while excluding air, tamping the snow to expel carbon dioxide gas and then compressing the snow.

6. The method of making dense masses of solid carbon dioxide, which includes expand ing liquid carbon dioxide to make snow and, while excluding air, tamping the snow to expel carbon-dioxide gas and then compressing the snow transversely to the direction of mg -7. The method of making dense masses of solid carbon dioxide, which includesexpanding liquidcarbon dioxide to make snow and, while excluding air, compacting the snow in a mold and then compressing it to a desired higher density by pressure applied transversely to the direction of compacting.

. 8. The method of making dense masses of solid carbon dioxide, which includes expanding liquid carbon dioxide to make snow,

breaking up the deposited snow, compacting.

it in one direction and then compressing it transversely to the direction of compacting. 9. A method of forming a block of dense structurally sound solid carbon dioxide which includes temp snow to expe the gases therefrom.

- 10. A method of forming a block of dense structurally sound solid carbon dioxide which includes tamping a mass of carbon dioxide mg a mass of carbon dioxide snow to expel the gases therefrom and .subee 

